src/share/vm/asm/assembler.cpp

Fri, 27 Feb 2009 13:27:09 -0800

author
twisti
date
Fri, 27 Feb 2009 13:27:09 -0800
changeset 1040
98cb887364d3
parent 815
eb28cf662f56
child 1057
56aae7be60d4
permissions
-rw-r--r--

6810672: Comment typos
Summary: I have collected some typos I have found while looking at the code.
Reviewed-by: kvn, never

duke@435 1 /*
xdono@772 2 * Copyright 1997-2008 Sun Microsystems, Inc. All Rights Reserved.
duke@435 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
duke@435 4 *
duke@435 5 * This code is free software; you can redistribute it and/or modify it
duke@435 6 * under the terms of the GNU General Public License version 2 only, as
duke@435 7 * published by the Free Software Foundation.
duke@435 8 *
duke@435 9 * This code is distributed in the hope that it will be useful, but WITHOUT
duke@435 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
duke@435 11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
duke@435 12 * version 2 for more details (a copy is included in the LICENSE file that
duke@435 13 * accompanied this code).
duke@435 14 *
duke@435 15 * You should have received a copy of the GNU General Public License version
duke@435 16 * 2 along with this work; if not, write to the Free Software Foundation,
duke@435 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
duke@435 18 *
duke@435 19 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
duke@435 20 * CA 95054 USA or visit www.sun.com if you need additional information or
duke@435 21 * have any questions.
duke@435 22 *
duke@435 23 */
duke@435 24
duke@435 25 #include "incls/_precompiled.incl"
duke@435 26 #include "incls/_assembler.cpp.incl"
duke@435 27
duke@435 28
duke@435 29 // Implementation of AbstractAssembler
duke@435 30 //
duke@435 31 // The AbstractAssembler is generating code into a CodeBuffer. To make code generation faster,
duke@435 32 // the assembler keeps a copy of the code buffers boundaries & modifies them when
duke@435 33 // emitting bytes rather than using the code buffers accessor functions all the time.
twisti@1040 34 // The code buffer is updated via set_code_end(...) after emitting a whole instruction.
duke@435 35
duke@435 36 AbstractAssembler::AbstractAssembler(CodeBuffer* code) {
duke@435 37 if (code == NULL) return;
duke@435 38 CodeSection* cs = code->insts();
duke@435 39 cs->clear_mark(); // new assembler kills old mark
duke@435 40 _code_section = cs;
duke@435 41 _code_begin = cs->start();
duke@435 42 _code_limit = cs->limit();
duke@435 43 _code_pos = cs->end();
duke@435 44 _oop_recorder= code->oop_recorder();
duke@435 45 if (_code_begin == NULL) {
duke@435 46 vm_exit_out_of_memory1(0, "CodeCache: no room for %s", code->name());
duke@435 47 }
duke@435 48 }
duke@435 49
duke@435 50 void AbstractAssembler::set_code_section(CodeSection* cs) {
duke@435 51 assert(cs->outer() == code_section()->outer(), "sanity");
duke@435 52 assert(cs->is_allocated(), "need to pre-allocate this section");
duke@435 53 cs->clear_mark(); // new assembly into this section kills old mark
duke@435 54 _code_section = cs;
duke@435 55 _code_begin = cs->start();
duke@435 56 _code_limit = cs->limit();
duke@435 57 _code_pos = cs->end();
duke@435 58 }
duke@435 59
duke@435 60 // Inform CodeBuffer that incoming code and relocation will be for stubs
duke@435 61 address AbstractAssembler::start_a_stub(int required_space) {
duke@435 62 CodeBuffer* cb = code();
duke@435 63 CodeSection* cs = cb->stubs();
duke@435 64 assert(_code_section == cb->insts(), "not in insts?");
duke@435 65 sync();
duke@435 66 if (cs->maybe_expand_to_ensure_remaining(required_space)
duke@435 67 && cb->blob() == NULL) {
duke@435 68 return NULL;
duke@435 69 }
duke@435 70 set_code_section(cs);
duke@435 71 return pc();
duke@435 72 }
duke@435 73
duke@435 74 // Inform CodeBuffer that incoming code and relocation will be code
duke@435 75 // Should not be called if start_a_stub() returned NULL
duke@435 76 void AbstractAssembler::end_a_stub() {
duke@435 77 assert(_code_section == code()->stubs(), "not in stubs?");
duke@435 78 sync();
duke@435 79 set_code_section(code()->insts());
duke@435 80 }
duke@435 81
duke@435 82 // Inform CodeBuffer that incoming code and relocation will be for stubs
duke@435 83 address AbstractAssembler::start_a_const(int required_space, int required_align) {
duke@435 84 CodeBuffer* cb = code();
duke@435 85 CodeSection* cs = cb->consts();
duke@435 86 assert(_code_section == cb->insts(), "not in insts?");
duke@435 87 sync();
duke@435 88 address end = cs->end();
duke@435 89 int pad = -(intptr_t)end & (required_align-1);
duke@435 90 if (cs->maybe_expand_to_ensure_remaining(pad + required_space)) {
duke@435 91 if (cb->blob() == NULL) return NULL;
duke@435 92 end = cs->end(); // refresh pointer
duke@435 93 }
duke@435 94 if (pad > 0) {
duke@435 95 while (--pad >= 0) { *end++ = 0; }
duke@435 96 cs->set_end(end);
duke@435 97 }
duke@435 98 set_code_section(cs);
duke@435 99 return end;
duke@435 100 }
duke@435 101
duke@435 102 // Inform CodeBuffer that incoming code and relocation will be code
duke@435 103 // Should not be called if start_a_const() returned NULL
duke@435 104 void AbstractAssembler::end_a_const() {
duke@435 105 assert(_code_section == code()->consts(), "not in consts?");
duke@435 106 sync();
duke@435 107 set_code_section(code()->insts());
duke@435 108 }
duke@435 109
duke@435 110
duke@435 111 void AbstractAssembler::flush() {
duke@435 112 sync();
duke@435 113 ICache::invalidate_range(addr_at(0), offset());
duke@435 114 }
duke@435 115
duke@435 116
duke@435 117 void AbstractAssembler::a_byte(int x) {
duke@435 118 emit_byte(x);
duke@435 119 }
duke@435 120
duke@435 121
duke@435 122 void AbstractAssembler::a_long(jint x) {
duke@435 123 emit_long(x);
duke@435 124 }
duke@435 125
duke@435 126 // Labels refer to positions in the (to be) generated code. There are bound
duke@435 127 // and unbound
duke@435 128 //
duke@435 129 // Bound labels refer to known positions in the already generated code.
duke@435 130 // offset() is the position the label refers to.
duke@435 131 //
duke@435 132 // Unbound labels refer to unknown positions in the code to be generated; it
duke@435 133 // may contain a list of unresolved displacements that refer to it
duke@435 134 #ifndef PRODUCT
duke@435 135 void AbstractAssembler::print(Label& L) {
duke@435 136 if (L.is_bound()) {
duke@435 137 tty->print_cr("bound label to %d|%d", L.loc_pos(), L.loc_sect());
duke@435 138 } else if (L.is_unbound()) {
duke@435 139 L.print_instructions((MacroAssembler*)this);
duke@435 140 } else {
duke@435 141 tty->print_cr("label in inconsistent state (loc = %d)", L.loc());
duke@435 142 }
duke@435 143 }
duke@435 144 #endif // PRODUCT
duke@435 145
duke@435 146
duke@435 147 void AbstractAssembler::bind(Label& L) {
duke@435 148 if (L.is_bound()) {
duke@435 149 // Assembler can bind a label more than once to the same place.
duke@435 150 guarantee(L.loc() == locator(), "attempt to redefine label");
duke@435 151 return;
duke@435 152 }
duke@435 153 L.bind_loc(locator());
duke@435 154 L.patch_instructions((MacroAssembler*)this);
duke@435 155 }
duke@435 156
duke@435 157 void AbstractAssembler::generate_stack_overflow_check( int frame_size_in_bytes) {
duke@435 158 if (UseStackBanging) {
duke@435 159 // Each code entry causes one stack bang n pages down the stack where n
duke@435 160 // is configurable by StackBangPages. The setting depends on the maximum
duke@435 161 // depth of VM call stack or native before going back into java code,
duke@435 162 // since only java code can raise a stack overflow exception using the
duke@435 163 // stack banging mechanism. The VM and native code does not detect stack
duke@435 164 // overflow.
duke@435 165 // The code in JavaCalls::call() checks that there is at least n pages
duke@435 166 // available, so all entry code needs to do is bang once for the end of
duke@435 167 // this shadow zone.
duke@435 168 // The entry code may need to bang additional pages if the framesize
duke@435 169 // is greater than a page.
duke@435 170
duke@435 171 const int page_size = os::vm_page_size();
duke@435 172 int bang_end = StackShadowPages*page_size;
duke@435 173
duke@435 174 // This is how far the previous frame's stack banging extended.
duke@435 175 const int bang_end_safe = bang_end;
duke@435 176
duke@435 177 if (frame_size_in_bytes > page_size) {
duke@435 178 bang_end += frame_size_in_bytes;
duke@435 179 }
duke@435 180
duke@435 181 int bang_offset = bang_end_safe;
duke@435 182 while (bang_offset <= bang_end) {
duke@435 183 // Need at least one stack bang at end of shadow zone.
duke@435 184 bang_stack_with_offset(bang_offset);
duke@435 185 bang_offset += page_size;
duke@435 186 }
duke@435 187 } // end (UseStackBanging)
duke@435 188 }
duke@435 189
duke@435 190 void Label::add_patch_at(CodeBuffer* cb, int branch_loc) {
duke@435 191 assert(_loc == -1, "Label is unbound");
duke@435 192 if (_patch_index < PatchCacheSize) {
duke@435 193 _patches[_patch_index] = branch_loc;
duke@435 194 } else {
duke@435 195 if (_patch_overflow == NULL) {
duke@435 196 _patch_overflow = cb->create_patch_overflow();
duke@435 197 }
duke@435 198 _patch_overflow->push(branch_loc);
duke@435 199 }
duke@435 200 ++_patch_index;
duke@435 201 }
duke@435 202
duke@435 203 void Label::patch_instructions(MacroAssembler* masm) {
duke@435 204 assert(is_bound(), "Label is bound");
duke@435 205 CodeBuffer* cb = masm->code();
duke@435 206 int target_sect = CodeBuffer::locator_sect(loc());
duke@435 207 address target = cb->locator_address(loc());
duke@435 208 while (_patch_index > 0) {
duke@435 209 --_patch_index;
duke@435 210 int branch_loc;
duke@435 211 if (_patch_index >= PatchCacheSize) {
duke@435 212 branch_loc = _patch_overflow->pop();
duke@435 213 } else {
duke@435 214 branch_loc = _patches[_patch_index];
duke@435 215 }
duke@435 216 int branch_sect = CodeBuffer::locator_sect(branch_loc);
duke@435 217 address branch = cb->locator_address(branch_loc);
duke@435 218 if (branch_sect == CodeBuffer::SECT_CONSTS) {
duke@435 219 // The thing to patch is a constant word.
duke@435 220 *(address*)branch = target;
duke@435 221 continue;
duke@435 222 }
duke@435 223
duke@435 224 #ifdef ASSERT
duke@435 225 // Cross-section branches only work if the
duke@435 226 // intermediate section boundaries are frozen.
duke@435 227 if (target_sect != branch_sect) {
duke@435 228 for (int n = MIN2(target_sect, branch_sect),
duke@435 229 nlimit = (target_sect + branch_sect) - n;
duke@435 230 n < nlimit; n++) {
duke@435 231 CodeSection* cs = cb->code_section(n);
duke@435 232 assert(cs->is_frozen(), "cross-section branch needs stable offsets");
duke@435 233 }
duke@435 234 }
duke@435 235 #endif //ASSERT
duke@435 236
duke@435 237 // Push the target offset into the branch instruction.
duke@435 238 masm->pd_patch_instruction(branch, target);
duke@435 239 }
duke@435 240 }
duke@435 241
duke@435 242
duke@435 243 void AbstractAssembler::block_comment(const char* comment) {
duke@435 244 if (sect() == CodeBuffer::SECT_INSTS) {
duke@435 245 code_section()->outer()->block_comment(offset(), comment);
duke@435 246 }
duke@435 247 }
duke@435 248
coleenp@672 249 bool MacroAssembler::needs_explicit_null_check(intptr_t offset) {
coleenp@672 250 // Exception handler checks the nmethod's implicit null checks table
coleenp@672 251 // only when this method returns false.
coleenp@672 252 if (UseCompressedOops) {
coleenp@672 253 // The first page after heap_base is unmapped and
coleenp@672 254 // the 'offset' is equal to [heap_base + offset] for
coleenp@672 255 // narrow oop implicit null checks.
coleenp@672 256 uintptr_t heap_base = (uintptr_t)Universe::heap_base();
coleenp@672 257 if ((uintptr_t)offset >= heap_base) {
coleenp@672 258 // Normalize offset for the next check.
coleenp@672 259 offset = (intptr_t)(pointer_delta((void*)offset, (void*)heap_base, 1));
coleenp@672 260 }
coleenp@672 261 }
coleenp@672 262 return offset < 0 || os::vm_page_size() <= offset;
coleenp@672 263 }
duke@435 264
duke@435 265 #ifndef PRODUCT
duke@435 266 void Label::print_instructions(MacroAssembler* masm) const {
duke@435 267 CodeBuffer* cb = masm->code();
duke@435 268 for (int i = 0; i < _patch_index; ++i) {
duke@435 269 int branch_loc;
duke@435 270 if (i >= PatchCacheSize) {
duke@435 271 branch_loc = _patch_overflow->at(i - PatchCacheSize);
duke@435 272 } else {
duke@435 273 branch_loc = _patches[i];
duke@435 274 }
duke@435 275 int branch_pos = CodeBuffer::locator_pos(branch_loc);
duke@435 276 int branch_sect = CodeBuffer::locator_sect(branch_loc);
duke@435 277 address branch = cb->locator_address(branch_loc);
duke@435 278 tty->print_cr("unbound label");
duke@435 279 tty->print("@ %d|%d ", branch_pos, branch_sect);
duke@435 280 if (branch_sect == CodeBuffer::SECT_CONSTS) {
duke@435 281 tty->print_cr(PTR_FORMAT, *(address*)branch);
duke@435 282 continue;
duke@435 283 }
duke@435 284 masm->pd_print_patched_instruction(branch);
duke@435 285 tty->cr();
duke@435 286 }
duke@435 287 }
duke@435 288 #endif // ndef PRODUCT

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